Lightroom Classic can't backup and optimize catalog

[GUGU_HW]

The following has been tested on both Windows11 24H2 and macOS 26's latest LrC build(14.5.1), and also for both external and internal drive to store the catalog.

My catalog is somehow big, 60GB, but not too big. I find that LrC keeps failing for backing up the catalog. After a track, I find that it successfully copied the catalog. But when zipping the catalog, it will fail and says that it may be disk space or permission issue. But I tracked that at the time it fails, there's still plenty free disk space, and right before error, the partial zip file created has a size of just slightly smaller than the unzipped files, meaning that zipping seems to just to be succeeded but somehow runs into an error. So currently I have to fall back to manually copying and zipping backups, but not let LrC one-click do this.

Because catalog optimization happens after a successful backup if not manually triggered, I have to manually issue catalog optimization. And it was when I find another bug. Unlike an error for backing up, in optimization, my catalog will hung LrC and the optimizing popup window will never close. I first tried in Windows and it won't finish after an hour, with LrC's process rarely use CPU at that time. Clicking stop will also make no effect except the button becomes grey and says stopping. I have to manually kill the process, but after that my catalog is fine and says that last optimization time is about half an hour after I first clicked optimize. Then I switched to macOS and let the optimization run for the whole night. After wake up, I find that the optimization still hasn't end and also with very small CPU usage for the process. In this run I have let LrC run for 12 hours, and the CPU time has used 4 hours. Clicking stop is same as Windows, with no effect and I need to kill the process. This time after next start it shows my catalog's last optimization time about one and a half hour after I started optimization.
For backup, because the catalog is fine (passed the integrety check before automatic backup procedure) and manually copy-zipping is fine, I think it's a bug which makes LrC fails to zip. For optimization, because after killing LrC and restart it will show a last optimization time of after starting and way before killing, although I'm not sure whether the optimization acutally succeeded, but I guess it succeded at that time, but some deadlock or something blocked LrC to detect this and goes to the optimization finish procedure of the UI. Because manually stopping also won't work, I may assume there's a deadlock between the frontend and the backend, because at that time the process nearly use any CPU.
I can't find relevent information currently. Any help will be appreciated.

[JohanElzenga · Accepted solution]

This issue is being reported here about once a week if not more. Most likely this is due to catalog corruption. Lightroom Classic 14.5 seems to be more picky about that than previous versions. What you could try is this: Create a brand new catalog and choose 'File - Import from Another Catalog'. Select your old catalog to import. In the import dialog choose to import all photos, but do not move them. This will create an exact copy of your old catalog, but usually without the corruption. The only thing that won't come across is any publishing services you may have. You will have to recreate those. If you synced your catalog then you will have to enable sync for the new catalog. There are some reports that this could cause a problem. Here’s how to solve that: https://www.danhartfordphoto.com/blog/2025/1/lr026-fixing-sync-problems-caused-by-switching-the-sync...

If importing as catalog does not work, then what usually does work is first downgrading to 14.4, and importing the catalog into a new catalog with that version. After that has worked successfully and the new catalog can be backed up, you can then update Lightroom Classic again to 14.5. Do note that 14.5 is not verified to work on MacOS 26, however. Having upgraded MacOS before there is a compatible version of Lightroom Classic might have complicated things.

[GUGU_HW]

Thanks, it worked.